Assessment of the efficacy of a product, in particular a medical product, is meaningful when the protocol for validating one particular product is reliable and repeatable in a consistent and comparable manner.
Such reliable and repeatable protocols are however not always available. For instance, the evaluation of the hemostatic performance of a product is very difficult as there is no method available for consistent assessment of the bleeding severity of wounds. In addition, there is no method available that would be applicable to any surgical procedure for use for example in a clinical investigation assessing the performance of the hemostatic agent.
An estimate of total intraoperative blood loss is an integral part of any surgical procedure and is considered routine care. The wide variety of surgical specialties and operations make quantitative standardization of total blood loss difficult, yet estimates may still be provided. Estimating total blood loss during a surgical procedure, supplemented with other variables such as blood pressure, are data helpful for the ongoing evaluation of the condition of a subject and the assessment/modification of intra- and post-operative management.
Adams et al. have described a sketched scale in the publication entitled “Acute in-vivo evaluation of bleeding with Gelfoam plus saline and Gelfoam plus human thrombin using a liver square lesion model in swine” (J Thromb Thrombolysis. 2009 July; 28(1):1-5. doi: 10.1007/s11239-008-0249-3. Epub 2008 July 16) used for assessing hemostasis or residual bleeding after placement of a product, in particular Gelfoam (which is produced by Baxter). There is however no indication of how bleeding severity is established during intra-operative inclusion/exclusion assessment before randomization, in particular before investigational device placement. Such scale further appears not to be adapted to be used consistently to assess success/failure of a product vs. hemostasis. This proposed scale does not include the full range of potential input and output domain data values for each proposed site, e.g. it does not include or distinguish life threatening as well as severe bleeding.
There does not appear to be correlation of the amount of blood associated with any score at any site to an objective measure of this amount of blood, e.g. weight of blood loss over a pre-specified time. There is thus a need for a score representative of a comparable amount of blood mass or flow across the various anatomic sites and under various potentially significant conditions (covariates).
A goal of the invention is to propose a system and method to simulate surface bleedings and validate a bleeding severity assessment scale for further application, during surgery and/or in clinical trials for example.
A goal of the invention is in particular to provide a method that enables establishing a bleeding severity during intra-operative inclusion/exclusion assessment before randomization and investigational device placement.
Another goal of the invention is to provide a surface bleeding severity scale to be used for the consistent assessment of hemostatic success or failure. It would preferably include the full range of any potential input and output domain data values expected for bleeding severities seen during elective surgical procedures.
A further goal of the invention is to provide a system and method to create a surface bleeding model allowing for consistency in the assessments of success/failure of hemostasis, while not being dependent on an individual animal physiology.
Still another goal of the invention is to provide a system and method to ensure consistency of bleeding severity assessments across investigators testing a particular product, in particular in a clinical investigation, to ensure notably that similar bleeding severities are enrolled during the investigation.
A specific goal of the invention is to provide a system and method to be used during a clinical study of a hemostatic product, in particular to determine intraoperative eligibility of patients, as well as hemostatic success of the tested product. In particular a goal is to ensure consistent enrollment of target bleeding sites of bleeding severities to be treated for assessment of the hemostatic product under investigation and help ensure subject safety by excluding those who have a too severe bleeding.
Still another goal on the invention is to provide a system and method to help training and testing investigators to recognize a specific degree of surface bleeding and homogeneously assess such surface bleeding in a clinical investigation.